Eevee: Add Glossy Reflection clamping

This enables reducing the noise comming from very bright light sources
(like a sun) that can be found in distant HDRIs.

The lost energy may be replaced manually by a sunlight that compensate the
this loss.

This clamping only concerns Reflection Cubmaps and is done on all on all
of them.

Setting to 0.0 disables it (default).

6 files changed, 42 insertions, 11 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lightcache.c b/source/blender/draw/engines/eevee/eevee_lightcache.c
index 873a63db355..3b6c21ee1b7 100644
--- a/source/blender/draw/engines/eevee/eevee_lightcache.c
+++ b/source/blender/draw/engines/eevee/eevee_lightcache.c
@@ -118,7 +118,6 @@ typedef struct EEVEE_LightBake {
 	int grid_sample_len;             /* Total number of samples for the current grid. */
 	int grid_curr;                   /* Nth grid in the cache being rendered. */
 	int bounce_curr, bounce_len;     /* The current light bounce being evaluated. */
-	float vis_range, vis_blur;       /* Sample Visibility compression and bluring. */
 	float vis_res;                   /* Resolution of the Visibility shadowmap. */
 	GPUTexture *grid_prev;           /* Result of previous light bounce. */
 	LightProbe **grid_prb;           /* Pointer to the id.data of the probe object. */
@@ -127,9 +126,6 @@ typedef struct EEVEE_LightBake {
 	EEVEE_LightProbe *cube;          /* Current probe being rendered (UBO data). */
 	int ref_cube_res;                /* Target cubemap at MIP 0. */
 	int cube_offset;                 /* Index of the current cube. */
-	float probemat[6][4][4];         /* ViewProjection matrix for each cube face. */
-	float texel_size, padding_size;  /* Texel and padding size for the final octahedral map. */
-	float roughness;                 /* Roughness level of the current mipmap. */
 	LightProbe **cube_prb;           /* Pointer to the id.data of the probe object. */
 
 	/* Dummy Textures */
@@ -745,12 +741,21 @@ static void eevee_lightbake_render_world_sample(void *ved, void *user_data)
 	EEVEE_LightBake *lbake = (EEVEE_LightBake *)user_data;
 	Scene *scene_eval = DEG_get_evaluated_scene(lbake->depsgraph);
 	LightCache *lcache = scene_eval->eevee.light_cache;
+	float clamp = scene_eval->eevee.gi_glossy_clamp;
 
 	/* TODO do this once for the whole bake when we have independent DRWManagers. */
 	eevee_lightbake_cache_create(vedata, lbake);
 
+	sldata->common_data.ray_type = EEVEE_RAY_GLOSSY;
+	sldata->common_data.ray_depth = 1;
+	DRW_uniformbuffer_update(sldata->common_ubo, &sldata->common_data);
+	EEVEE_lightbake_render_world(sldata, vedata, lbake->rt_fb);
+	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake->rt_color, lbake->store_fb, 0, 1.0f, lcache->mips_len, clamp);
+
+	sldata->common_data.ray_type = EEVEE_RAY_DIFFUSE;
+	sldata->common_data.ray_depth = 1;
+	DRW_uniformbuffer_update(sldata->common_ubo, &sldata->common_data);
 	EEVEE_lightbake_render_world(sldata, vedata, lbake->rt_fb);
-	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake->rt_color, lbake->store_fb, 0, 1.0f, lcache->mips_len);
 	EEVEE_lightbake_filter_diffuse(sldata, vedata, lbake->rt_color, lbake->store_fb, 0, 1.0f);
 
 	/* Clear the cache to avoid white values in the grid. */
@@ -919,6 +924,7 @@ static void eevee_lightbake_render_probe_sample(void *ved, void *user_data)
 	LightCache *lcache = scene_eval->eevee.light_cache;
 	EEVEE_LightProbe *eprobe = lbake->cube;
 	LightProbe *prb = *lbake->probe;
+	float clamp = scene_eval->eevee.gi_glossy_clamp;
 
 	/* TODO do this once for the whole bake when we have independent DRWManagers. */
 	eevee_lightbake_cache_create(vedata, lbake);
@@ -932,7 +938,8 @@ static void eevee_lightbake_render_probe_sample(void *ved, void *user_data)
 	DRW_uniformbuffer_update(sldata->common_ubo, &sldata->common_data);
 
 	EEVEE_lightbake_render_scene(sldata, vedata, lbake->rt_fb, eprobe->position, prb->clipsta, prb->clipend);
-	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake->rt_color, lbake->store_fb, lbake->cube_offset, prb->intensity, lcache->mips_len);
+	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake->rt_color, lbake->store_fb, lbake->cube_offset,prb->intensity,
+	                              lcache->mips_len, clamp);
 
 	lcache->cube_len += 1;
 
@@ -1167,6 +1174,7 @@ void EEVEE_lightbake_job(void *custom_data, short *stop, short *do_update, float
 void EEVEE_lightbake_update_world_quick(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, const Scene *scene)
 {
 	LightCache *lcache = vedata->stl->g_data->light_cache;
+	float clamp = scene->eevee.gi_glossy_clamp;
 
 	EEVEE_LightBake lbake = {
 		.resource_only = true
@@ -1181,7 +1189,7 @@ void EEVEE_lightbake_update_world_quick(EEVEE_ViewLayerData *sldata, EEVEE_Data
 	sldata->common_data.ray_depth = 1;
 	DRW_uniformbuffer_update(sldata->common_ubo, &sldata->common_data);
 	EEVEE_lightbake_render_world(sldata, vedata, lbake.rt_fb);
-	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake.rt_color, lbake.store_fb, 0, 1.0f, lcache->mips_len);
+	EEVEE_lightbake_filter_glossy(sldata, vedata, lbake.rt_color, lbake.store_fb, 0, 1.0f, lcache->mips_len, clamp);
 
 	sldata->common_data.ray_type = EEVEE_RAY_DIFFUSE;
 	sldata->common_data.ray_depth = 1;
diff --git a/source/blender/draw/engines/eevee/eevee_lightprobes.c b/source/blender/draw/engines/eevee/eevee_lightprobes.c
index e4659306f5c..56690551e9c 100644
--- a/source/blender/draw/engines/eevee/eevee_lightprobes.c
+++ b/source/blender/draw/engines/eevee/eevee_lightprobes.c
@@ -376,6 +376,7 @@ void EEVEE_lightbake_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata,
 		DRW_shgroup_uniform_float(grp, "lodMax", &pinfo->lod_rt_max, 1);
 		DRW_shgroup_uniform_float(grp, "texelSize", &pinfo->texel_size, 1);
 		DRW_shgroup_uniform_float(grp, "paddingSize", &pinfo->padding_size, 1);
+		DRW_shgroup_uniform_float(grp, "fireflyFactor", &pinfo->firefly_fac, 1);
 		DRW_shgroup_uniform_int(grp, "Layer", &pinfo->layer, 1);
 		DRW_shgroup_uniform_texture(grp, "texHammersley", e_data.hammersley);
 		// DRW_shgroup_uniform_texture(grp, "texJitter", e_data.jitter);
@@ -1102,7 +1103,7 @@ static void eevee_lightbake_render_scene_to_planars(
 void EEVEE_lightbake_filter_glossy(
         EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata,
         struct GPUTexture *rt_color, struct GPUFrameBuffer *fb,
-        int probe_idx, float intensity, int maxlevel)
+        int probe_idx, float intensity, int maxlevel, float firefly_fac)
 {
 	EEVEE_PassList *psl = vedata->psl;
 	EEVEE_LightProbesInfo *pinfo = sldata->probes;
@@ -1151,6 +1152,7 @@ void EEVEE_lightbake_filter_glossy(
 
 		pinfo->samples_len_inv = 1.0f / pinfo->samples_len;
 		pinfo->lodfactor = bias + 0.5f * log((float)(target_size * target_size) * pinfo->samples_len_inv) / log(2);
+		pinfo->firefly_fac = (firefly_fac > 0.0) ? firefly_fac : 1e16;
 
 		GPU_framebuffer_ensure_config(&fb, {
 			GPU_ATTACHMENT_NONE,
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 09e444c40b2..c18be0f43b1 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -480,6 +480,7 @@ typedef struct EEVEE_LightProbesInfo {
 	float near_clip;
 	float far_clip;
 	float roughness;
+	float firefly_fac;
 	float lodfactor;
 	float lod_rt_max, lod_cube_max, lod_planar_max;
 	float visibility_range;
@@ -888,7 +889,7 @@ void EEVEE_lightbake_render_scene(
         const float pos[3], float near_clip, float far_clip);
 void EEVEE_lightbake_filter_glossy(
         EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, struct GPUTexture *rt_color, struct GPUFrameBuffer *fb,
-        int probe_idx, float intensity, int maxlevel);
+        int probe_idx, float intensity, int maxlevel, float firefly_fac);
 void EEVEE_lightbake_filter_diffuse(
         EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata, struct GPUTexture *rt_color, struct GPUFrameBuffer *fb,
         int grid_offset, float intensity);
diff --git a/source/blender/draw/engines/eevee/shaders/lightprobe_filter_glossy_frag.glsl b/source/blender/draw/engines/eevee/shaders/lightprobe_filter_glossy_frag.glsl
index bb23051b7e5..fdfee54f368 100644
--- a/source/blender/draw/engines/eevee/shaders/lightprobe_filter_glossy_frag.glsl
+++ b/source/blender/draw/engines/eevee/shaders/lightprobe_filter_glossy_frag.glsl
@@ -6,11 +6,17 @@ uniform float lodFactor;
 uniform float lodMax;
 uniform float paddingSize;
 uniform float intensityFac;
+uniform float fireflyFactor;
 
 in vec3 worldPosition;
 
 out vec4 FragColor;
 
+float brightness(vec3 c)
+{
+	return max(max(c.r, c.g), c.b);
+}
+
 vec3 octahedral_to_cubemap_proj(vec2 co)
 {
 	co = co * 2.0 - 1.0;
@@ -77,7 +83,13 @@ void main() {
 			/* http://http.developer.nvidia.com/GPUGems3/gpugems3_ch20.html : Equation 13 */
 			float lod = clamp(lodFactor - 0.5 * log2(pdf * dist), 0.0, lodMax) ;
 
-			out_radiance += textureLod(probeHdr, L, lod).rgb * NL;
+			vec3 l_col = textureLod(probeHdr, L, lod).rgb;
+
+			/* Clamped brightness. */
+			float luma = max(1e-8, brightness(l_col));
+			l_col *= 1.0 - max(0.0, luma - fireflyFactor) / luma;
+
+			out_radiance += l_col * NL;
 			weight += NL;
 		}
 	}
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 3ad96f09555..a4ceaf04942 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -1461,7 +1461,7 @@ typedef struct SceneEEVEE {
 	int gi_cubemap_resolution;
 	int gi_visibility_resolution;
 	float gi_irradiance_smoothing;
-	float pad;
+	float gi_glossy_clamp;
 
 	float gi_cubemap_draw_size;
 	float gi_irradiance_draw_size;
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 850560646ec..23e8b13be42 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -5687,6 +5687,14 @@ static void rna_def_scene_eevee(BlenderRNA *brna)
 	RNA_def_property_ui_range(prop, 0.0f, 1.0f, 5, 2);
 	RNA_def_property_float_default(prop, 0.1f);
 	RNA_def_property_ui_text(prop, "Irradiance Smoothing", "Smoother irradiance interpolation but introduce light bleeding");
+	RNA_def_property_override_flag(prop, PROPOVERRIDE_OVERRIDABLE_STATIC);
+
+	prop = RNA_def_property(srna, "gi_glossy_clamp", PROP_FLOAT, PROP_NONE);
+	RNA_def_property_float_default(prop, 0.0f);
+	RNA_def_property_ui_text(prop, "Clamp Glossy", "Clamp pixel intensity to reduce noise inside glossy reflections "
+	                                               "from reflection cubemaps (0 to disabled)");
+	RNA_def_property_range(prop, 0.0f, FLT_MAX);
+	RNA_def_property_override_flag(prop, PROPOVERRIDE_OVERRIDABLE_STATIC);
 
 	prop = RNA_def_property(srna, "gi_show_irradiance", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", SCE_EEVEE_SHOW_IRRADIANCE);